1. Field of the Application
The application relates in general to a handheld electronic device and more particularly to a handheld electronic device for reducing electromagnetic interference.
2. Description of the Related Art
When being operated by a user, a mobile phone radiates signals around its receiver which might interfere with a hearing aid. In this regard, federal communications commission (FCC), according to which the mobile phone is requested to be tested for its compatibility with the hearing aid, establishes an act associated with hearing aid compatibility (HAC), so as to evaluate the adaptability and safety between the hearing aid and diverse communication apparatuses.
TABLE 1Regulation ofRegulation ofElectric FieldMagnetic FieldLevelStrength (V/m)Strength (A/m)M1149.6-266.10.45-0.8 M2 84.1-149.60.25-0.45M347.3-84.10.15-0.25M4<33.5<0.15
Referring to Table 1, according to the HAC act, manufactories of the mobile phone have to make the electromagnetic interference (EMI) of the mobile phone under a threshold value. The mentioned EMI can be categorized into the disturbances of electric field and magnetic field that affect the performance and endurability of hearing aid. In other words, HAC is provided to deal with not only the influence of electric field on the hearing aid, but also the disturbance of magnetic field on the hearing aid. Moreover, according to the FCC, the mobile phone is requested to comply with the level of M3 listed in table 1. That is, the electric field strength of mobile phone has to be lower than 84.1 V/m, and the magnetic field strength of mobile phone has to be lower than 0.25 A/m. Therefore, it is an important issue of the industrial endeavors to develop a mobile phone which complies with HAC act.